Hidradenitis suppurativa (HS) refers to a skin disorder of the apocrine glands (sweat glands found on certain parts of the body) and hair follicles in which swollen, painful, chronically inflamed lesions or lumps develop in the groin and sometimes under the arms and under the breasts. Hidradenitis suppurativa is characterized by recurrent inflamed nodules, abscesses, and fistulas, and it occurs when apocrine gland outlets become blocked by perspiration or are unable to drain normally because of incomplete gland development. Secretions trapped in the glands force perspiration and bacteria into surrounding tissue, causing subcutaneous induration, inflammation, and infection. Hidradenitis suppurativa is confined to areas of the body that contain apocrine glands. These areas are the axillae, areola of the nipple, groin, perineum, circumanal, and periumbilical regions.
HS is a chronic inflammatory skin disease, particularly of young adults, and affects approximately 1% of the general population in the West, with women affected 2 to 5 times more commonly than men (Naldi L. Epidemiology. In: Hidradenitis Suppurativa (Jemec G, Revuz J, Leyden J, eds). Heidelberg: Springer. 2006), and with an average age of onset of 23 years. The poorly understood disease is believed to be under-reported by those who suffer from it. HS is also associated with obesity and smoking.
The disease is associated with significant morbidity. Given the pain and consequent physical impairment associated with the tender lesions of this disease, it has been reported that health-related quality of life is lower for patients with hidradenitis suppurativa than other dermatological diseases. In addition, a recent study estimated that up to 20% of patients with HS report the co-existence of depression, and HS patients report a high level of stigmatization. Use of emergency services and antibiotics for incision and drainage of painful abscesses are high when lesions flare.
It is speculated that immunological abnormalities of the hair follicle play a role in the etiology of this disease, and that the underlying mechanisms may be pathogenetically related to those of Crohn's disease (Kurzen et al., Exp Dermatol. 17: 455-456, 2008).
Treatment options have been largely disappointing. Some researchers also suggest that changes in diet, warm compresses and baths, and zinc gluconate supplements can relieve symptoms of HS, bring about remission, and/or minimize recurrence.
To date, no systemic therapy has been demonstrated to be effective for HS in a randomized, double-blind, placebo-controlled trial. Non-evidence-based approaches for moderate to severe HS include long-term antibiotic therapy to control inflammation; case reports or series have described corticosteroids, cyclosporine, or methotrexate as occasionally effective. Surgical intervention is utilized for more advanced HS cases (Alikhan et al., J Am Acad Dermatol. 60: 539-561, 2009). That is, the evidentiary basis behind current therapies for moderate-severe disease, including short- or long-term oral or topical antibiotics, retinoids, intralesional steroids, oral steroids, immunosuppressive agents, radiation, laser therapy, or disfiguring surgical removal of involved areas in more severe cases, is largely limited to anecdotal experience or open-label studies. Surgery is the preferred treatment option in Europe. Currently, there are no approved therapies for this disease in the US.
While some recent case reports have described successful use of tumor necrosis factor-α (TNF-α) antagonists in HS (Haslund et al., Acta Derm Venereol. 89: 595-600, 2009), TNFα antagonists have met with limited success in treating HS. For example, a study examining treatment of HS with etanercept failed to show improvement of HS over a 24-week treatment period (Adams et al., Arch Dermatol. 146(5): 501-504, 2010).